1. Field of the Invention
The present invention generally relates to a system board device and, more particularly, to a system board device which is provided in a large-scale computer and is subjected to a forced air cooling.
A large-scale computer is provided with a system board device. Such a system board device includes a plurality of daughter boards mounted on a motherboard. Each of the daughter boards has a plurality of random-access memories (RAMs) mounted thereon. If a malfunction occurs in one of the RAMs mounted on one of the daughter boards, it is required to replace the one of the daughter boards which one has the malfunctioning RAM with a new daughter board. Generally, a number of RAMs provided in a single system board is as large as a few hundred to a few thousand. Accordingly, a malfunction frequently occurs in the RAMs as a whole, and a maintenance operation is frequently required for the system board device. Thus, it is preferable that the system board device be of an easy maintenance construction.
2. Description of the Related Art
FIG. 1 is an exploded perspective view of a conventional system board device 10. The system board device 10 is built in a large-scale computer 11. A ventilation cover 13 of the system board device 10 is fixed to a motherboard unit 12 by a plurality of screws 14. The motherboard unit 12 includes a motherboard 15 on which a plurality of electronic parts 16 are mounted. A plurality of daughter boards 18 are also mounted on the motherboard 15 with connectors therebetween so as to be perpendicular to the motherboard 15. A plurality of RAMs 17 are mounted on each of the daughter boards 18. The ventilation cover 13 is provided for forming a tunnel-like passage 19 so that air may flow therethrough. The ventilation cover 13 covers all of the electronic parts 16 and all of the daughter boards 18 so that the tunnel-like passage 19 accommodates all of the electronic parts 16 and all of the daughter boards 18.
When the large-scale computer 11 is in operation, a cooling fan 20 is operated so as to blow air upwardly. Thereby, external air is introduced into the large-scale computer 11 through the bottom side of the large-scale computer 11, and an upward air flow 21 is generated in the large-scale computer 11. The air flow 21 goes through the tunnel-like passage 19 so that heat generated by the electronic parts 16 and the RAMs 17 is removed therefrom by the air flow 21.
When a maintenance operation is performed so as to replace one of the daughter boards 18 which is malfunctioning with a new one, the ventilation cover 13 must be removed so that the daughter boards 18 are accessible.
In the conventional system board device 10, the ventilation cover 13 has a size almost the same as the size of the motherboard 15, and is secured to the motherboard 15 by the screws 14 at many positions. For example, the ventilation cover 13 is secured by five screws 14 on each side, and a total of ten screws are used to secure the ventilation cover 13 to the motherboard 15. Accordingly, in order to remove the ventilation cover 13, an unscrewing operation is performed for ten screws, which unscrewing operation takes a long time.
As mentioned above, there is a problem in that it takes a long time for the conventional system board device 10 to be prepared for a replacing operation of one of the daughter boards 18 which one is malfunctioning.